x1,y1,x2,y2=map(float,input().split())
a=(x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)
print(a**(1/2))
 x1,y1,x2,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 a=(x2-x1)*(x2-x1)+(y2-y1)*(y2-y1) a (x2-x1)*(x2-x1)+(y2-y1)*(y2-y1) (x2-x1)*(x2-x1) x2-x1 x2 x1 x2-x1 x2 x1 (y2-y1)*(y2-y1) y2-y1 y2 y1 y2-y1 y2 y1 print(a**(1/2)) print a**(1/2) a 1/2 1 2 y1,x2,y2=map(float,input().split()) map(float,input().split()) y1 x2,y2=map(float,input().split()) map(float,input().split()) x2 a=(x2-x1)*(x2-x1)+(y2-y1)*(y2-y1) (x2-x1)*(x2-x1)+(y2-y1)*(y2-y1) a x1,y1,x2,y2=map(float,input().split()) map(float,input().split()) x1 y2=map(float,input().split()) map(float,input().split()) y2
x1,y1,x2,y2=map(float,input().split())
a=(x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)
print(a**(1/2))

